#include <algorithm>
#include <bits/stdc++.h>
using namespace std;

int a[11]={5, 13, 19, 21, 37, 56, 64, 75, 80, 88, 92};

int main()
{
	//C++ stl 二分查找
	// std::upper_bound()
	// std::lower_bound()


	int x;
	cin>>x;
	int l=0,r=10;
	int ans;
	while(l<=r)
	{
		int mid=(l+r)/2;
		if(x==a[mid])
		{
			cout<<mid;
			return 0;
		}
		if(x<a[mid])
		{
			r=mid-1;
		}
		else
		{
			ans=mid;
			l=mid+1;
		}
	}
	cout<<"Not found!";
	
	return 0;	
}

//5
//1 -2 3 1 -4


